Serving as the unit's transducer is a state-of-the-art 21" woofer with 4.5" voice coil.This combination of high-quality materials and sophisticated magnetic drivers fields some pretty impressive results.Even very low bass frequencies are rendered with pinpoint precision and hairtrigger transient response, treating audiences to a breathtaking audio experience.Made of durable multiplex housing covered in robust black textured lacquer, the high-quality housing provides six carrying handles, an M20 pole mount, and bushings on the rear panel that accept casters. Pick-points for attaching DRK-10 and DRK-20 harnesses are built into the top panel to enable easy, safe stacking.